<template>
    <div class="selection-component">       <!--下拉框组件-->
        <div class="selection-show" @click="toggleDrop">
            <span>{{ selections[nowIndex].label }}</span>
            <div class="arrow"></div>
        </div>
        <div class="selection-list" v-if="isDrop">
            <ul>
                <li v-for="(item,index) in selections"
                  @click="chooseSelection(index)">{{ item.label }}</li>

            </ul>
        </div>
    </div>
</template>

<script>

    export default {
         props: {
           selections: {
             type: Array,
             default: [{
               label: 'test',
               value: 0
             }]
           }
         },
         data () {
           return {
             nowIndex: 0 ,
             isDrop: false      //下拉框显示隐藏
           }
         },
         methods: {
           toggleDrop () {
             this.isDrop = !this.isDrop     //切换下拉框
           },
           chooseSelection (index) {
             this.nowIndex = index
             this.isDrop= false
             this.$emit('on-change', this.selections[this.nowIndex])
           }
    }
  }
</script>

<style>
.selection-component {
    position: relative;
    display: inline-block;
}

.selection-show {
    border : 1px solid #e3e3e3;
    padding: 0 20px 0 10px;
    display: inline-block;
    position: relative;
    cursor: pointer;
    height: 25px;
    line-height: 25px;
    border-radius: 3px;
}

.selection-show .arrow {
    display:inline-block;
    border-left: 4px solid transparent; /*全透明黑色*/
    border-right: 4px solid transparent;
    border-top: 5px solid #e3e3e3;
    width: 0;
    height: 0;
    margin-top: -1px;
    margin-left: 6px;
    margin-right: -14px;
    vertical-align: middle;
}

.selection-list {
  display:inline-block;
  position: absolute;
  left: 0;
  top: 25px;
  width: 100%;
  background: #fff;
  border-top: 1pxx solid #e3e3e3;
  border-bottom: 1px solid #e3e3e3;
  z-index: 5;
}

.selection-list li {
  padding: 5px 5px 5px 10px;
  border-left: 1px solid #e3e3e3;
  border-right: 1px solid #e3e3e3;
  cursor: pointer;
  background: #fff;
  white-space: nowrap;
  overflow:hidden;
  text-overflow: ellipsis;
}

.selection-list li:hover {
  background: #e3e3e3;
}
</style>
